January 23, 2017 AT 7:00 am

Using Adafruit proto boards for Eurorack synth DIY

Thanks to Leigh for writing in to share this synth module DIY! Check out more info here.

Here’s a project I’ve been working on for a while. I am new to the Eurorack synthesizer world, and I’ve been wanting to find a way to build my own modules from scratch. Rather than deal with designing and fabricating printed circuit boards (PCBs), I wanted a way to quickly take circuits developed on a breadboard and implement them in my Eurorack setup. Enter the mighty Perma-Proto board, from Adafruit:

I have used these Perma-Proto boards on a number of other, non-synth projects before. They are high quality in construction (with thru-plated holes), and they offer a nice layout, with strips running down both sides for power rails. Size-wise, the ½ Size Perma-Protos are a pretty good match for Eurorack. Here’s one next to a Disting module – you can see it uses about 75% of the available height:

Adafruit also offers a full-sized version of the board, so you could get one of those and cut it down to exactly Eurorack size and gain another 10 rows or so of holes. But my goal was to make simpler designs with this setup anyways, so I hoped I could make the half-size version work, with less effort and less waste.

After settling on the board, I needed to figure out a few other construction basics:

What kind of jacks and potentiometers I could find that could solder directly to the breadboard (avoiding a tangle of wire leads going between the board and the panel, if possible), and where on the board could I solder them?

How to best assign the Perma-Proto board’s power rails (Eurorack uses a bipolar power supply, with positive, negative, and ground lines— but the board only has power bus lines labeled as + and –. However, the board has two pairs of these lines…)

Featured Adafruit Product!

Adafruit Perma-Proto Half-sized Breadboard PCB – 3 Pack!: Customers have asked us to carry basic perf-board, but we never liked the look of most basic perf: its always crummy quality, with pads that flake off and no labeling. Then we thought about how people actually prototype – usually starting with a solderless breadboard and then transferring the parts to a more permanent PCB. That’s when we realized what people would really like is a proto board that makes it easy! Read more.